Cooling Device with a Filter Unit

ABSTRACT

The invention relates to a cooling device comprising a cooling unit ( 10 ) that is penetrated by a fluid to be cooled, in particular hydraulic oil, and a filter unit ( 12 ) for filtering said fluid, the filter unit ( 12 ) extending along a longitudinal side of the cooling unit ( 10 ) and a fluid collecting space ( 16 ) being arranged between the filter unit ( 12 ) and the cooling unit ( 10 ). The invention is characterized in that the fluid collecting space ( 16 ) has a uniform flow cross-section and is at least partially closed against the filter unit ( 12 ) by a concavely curved limitating wall ( 36 ). The optimized fluid guidance obtained thereby results in a uniformisation of speed while at the same time avoiding cavities and turbulences in order to ensure a trouble-free and energetically favorable operation of the inventive cooling device.

The invention relates to a cooling device with a cooling unit throughwhich a fluid to be cooled, in particular hydraulic oil, can flow, andwith a filter unit for filtration of the fluid, the filter unitextending on one longitudinal side of the cooling unit and a fluidcollecting chamber being located between the filter unit and the coolingunit.

These cooling devices (U.S. Pat. No. 4,295,964, CH 533 246 A) can beused for a host of applications and are available in the most variedembodiments. The cooling device systems which have been readilyavailable on the market to date, however, all consist predominantly of afilter unit which is flanged to the cooling unit, or of tank units whichare connected to the cooling units, the respective tank unit thenholding the filter element. The known cooling devices are thereforegenerally composed of several components, and the independent coolingunit can be connected by way of the corresponding piping to theindependent filter unit as the cooling device is being produced. As aresult of the indicated piping, in the transport of the fluid,flow-induced losses occur; this does not favor energy-efficientoperation of the known cooling device. Nor can it be precluded thatleaks may occur in the area of the piping. This adversely affectsoperating reliability.

DE 196 35 777 A discloses a cooling device with a cooling unit throughwhich a fluid to be cooled can flow and with a filter unit forfiltration of the fluid, the cooling unit and the filter unit beingintegrally connected to one another and the filter unit together withthe cooling unit being located in a device housing. This document alsodiscloses using a plate-shaped finned radiator as the cooling unit andthe filter element is held in a filter housing in the known solutionsuch that it is an integral component of the device housing.

U.S. Pat. No. 5,159,821 moreover discloses a cooling device with afilter disk with a small structure in the axial direction as the filterelement which, located in the device housing, also holds a plate-shapedfinned radiator as the cooling unit. A drying medium extends in thefluid direction in front of the filter element within the devicehousing, the filter element disk which is connected upstream of thefinned radiator on one of its longitudinal sides occupying only a smalloverall length there. In these known solutions as well, flow lossesoccur in the operation of the filter device; this can lead to low filterefficiency. To some extent, a used filter element can be replaced by anew element only with great difficultly.

EP 1 261 809 B1 discloses a generic cooling device with a cooling unitthrough which a fluid to be cooled, especially hydraulic oil, can flow,and with a filter unit for filtration of the fluid, the cooling unit andthe filter unit being integrally connected to one another, whichtogether with the cooling unit is located in a device housing, thecooling unit as a plate-shaped finned radiator assuming the incipientcooling tasks. The filter unit is located in the flow direction of thefluid to be cooled upstream from the plate-shaped finned radiator; thishas the advantage that potential fouling, when filtered out of the fluidflow, cannot adversely affect reliable operation of the cooling unit. Inthe known solution the filter unit extends essentially along onelongitudinal side of the finned radiator, between the filter unit andthe cooling unit a fluid collecting chamber being connected. This fluidcollecting chamber has different cross sectional areas, in particular,the cross section widens in the direction of the bottom side of thecooling device so that unfavorable flow conditions can occur with cavityformation; this is disadvantageous for undisrupted, energy-savingoperation of the known cooling device and it has been found inparticular that at very low flow velocities of the fluid thedistribution of the latter out of the fluid collecting chamber to thecooling unit leads to nonuniform distribution situations. This adverselyaffects effective cooling of the fluid. In addition, the known solutionis expensive and complex to produce.

Proceeding from this prior art, the object of this invention is tofurther improve the known cooling devices such that they enablealtogether improved operation, especially also at low flow velocities.This object is achieved by a cooling device with the features of claim 1in its entirety.

In that, as specified in the characterizing part of claim 1, the fluidcollecting chamber has a uniform flow cross section and is sealedrelative to the filter unit at least partially by a concavely curvedboundary wall, optimized fluid routing is achieved which leads to thevelocity behavior becoming uniform while avoiding cavities andturbulence so that in this respect trouble-free, energy-efficientoperation is possible with the cooling device according to theinvention.

In particular, the free fluid cross section in the fluid collectingchamber can be adapted to the free flow cross sections in the area ofthe filter unit, its preferably being provided that the fluid collectingchamber is made semicircular in cross section, the filter unit having afilter element which is held in a filter housing with a cylindricalinstallation space. Thus, the free flow cross sections can continue andremain within the filter housing in the fluid collecting chamber so thatin spite of deflected flows in the area of the transition between thefilter housing and the fluid collecting chamber, for the most partproblem-free fluid transport is achieved.

In one especially preferred embodiment of the cooling device accordingto the invention, it is provided that the fluid collecting chamber inthe middle has another boundary wall which divides the fluid collectingchamber into two component spaces, of which one has a fluid connectionto the filter housing and the other has an outlet for discharge offiltered and cooled fluid. As a result of the other boundary wall in thefluid collecting chamber the fluid flow can be divided, one componentflow coming from the filter unit first being supplied to the part of thecooling unit, which flow, in the reverse direction and cooled by theother part of the cooling unit, re-enters the component space of thefluid collecting chamber bordered by the other boundary wall, in orderfrom there to leave the cooling device filtered and cooled. Thisarrangement is especially favorable for fluid flows to be routed with alow speed. By division and due to separation via the respective boundarywall the cooling and transport performances can be “proportioned”; thiscannot be achieved with the known, described solutions.

Other advantageous embodiments of the cooling device according to theinvention are the subject matter of the other dependent claims.

The cooling device according to the invention will be detailed belowusing one embodiment as shown in the drawings. The figures are schematicand not to scale.

FIG. 1 shows the cooling device as a whole, partially in a longitudinalsection, partially in a perspective top view;

FIG. 2 shows the structure of the filter housing and fluid collectingchamber located on the left viewed in the direction of looking at FIG.1, without the filter element inserted.

The cooling device shown in the figures has a cooling unit 10 throughwhich a fluid to be cooled, in particular, hydraulic oil, can flow, anda filter unit 12 for filtration of this fluid. The cooling unit 10 ismade as a plate-shaped finned radiator, i.e., to guide the cooling air,the plate radiator has fins (not shown) which are folded up in a zig-zagshape and which between themselves border fluid routing channels 14which are used to transport the fluid to be cooled. The direction of airrouting through the cooling unit 10 runs perpendicular to the plane ofFIG. 1 and the fluid transport direction transversely thereto, that is,within the plane of the figure. Furthermore, the stacked fluid routingchannels 14 discharge on either side into the fluid collecting chambers16, 18. The structure of these finned radiators is in generalconventional, so that it will no longer be detailed here. The devicehousing of the cooling unit 10 can consist of an aluminum casting or thelike; but it can also be composed in the conventional manner of sheetmetal parts in a box shape and can be assembled to form the overallhousing via weld connections. For the sake of simplicity, the upper andthe lower end wall for the collecting chamber 16 are not shown.

Viewed in the direction of looking at FIG. 1, the filter unit 12 extendson the left longitudinal side of the cooling unit 10 and the filter unit12 has a filter housing 20 on a cylindrical installation space 22 whichlies in the middle for holding a cylindrical filter element 24 ofconventional design. This filter unit 24 is made of conventionalfiltration materials and consists, for example, of a pleated, hollowcylindrical, multilayer filter mat which surrounds a middle support tubewhich is not detailed. Viewed in the direction of looking at FIG. 1, thefilter housing 20 in its upper end area has an inlet 26 for at leastpartially fouled and heated fluid. The fluid which has been supplied inthis way via the inlet 26 flows through the filter element 24 from theoutside to the inside and the filtered fluid is discharged in the middlefrom the filter element 24 through the bottom outlet opening 28 of aspacer layer 30. This spacer layer 30 is supported on a clip-like orcage-like holding unit 32 with individual holding rods 33, which in turnare supported on the bottom part 34 of the filter housing 20. Thisbottom part 34 can seal the filter unit 12 fluid-tight to the bottom,that is, on the bottom-side, but can also be used to hold a bypass valvewhich is not detailed in order for example to supply fouled fluidcleaned by the filter unit 12 not to the cooling unit 10 for coolingpurposes, but to drain it out of the device; this can be advantageous,for example, when the temperature of the filtered fluid does not yetnecessitate cooling or does so only partially.

By means of the holding unit 32 and the spacer layer 30 it is possibleto insert filter elements 24, which are different in terms of overalllength, into the same cooling device in order to perform variousfiltration tasks in practical applications. But preferably, as shown inFIG. 1, the overall length of the filter element 24 is chosen such thatin the axial direction only roughly half of the installation space 22 ofthe filter housing 20 is used up so that in this respect underneath thefilter element 24 a cylindrical holding space is formed which alsocontributes to making the fluid flow uniform in the filter housing 20after filtration.

As FIG. 1 furthermore shows, between the filter unit 12 and the coolingunit 10 is the first fluid collecting chamber 26 with an axial extensionlength which is adapted according to connection possibilities on thelongitudinal side of the finned radiator as the cooling unit 10. Thisfluid collecting chamber 16 has a uniform flow cross section and isclosed by a concavely curved boundary wall 36 relative to the filterunit 12. These conditions are especially clearly illustrated in FIG. 2.In this way, for the fluid collecting chamber 26 a type of semicirculartube is formed which with its flat connection cross section engages theface of the finned radiator.

Preferably the other or the second fluid collecting chamber 18 on theopposite longitudinal side of the finned radiator has a comparable halftube structure; here, however, the possibility also exists of selectinga different, in particular, square cross section. Furthermore, it isprovided that the fluid collecting chamber 18 continuously hasconnection possibilities to the fluid routing channels 14 of the coolingunit 10. In the embodiment shown in the figures, the fluid collectingchamber 16 is divided roughly in the middle by another boundary wall 38which divides the fluid collecting chamber 16 fluid-tight into twocomponent spaces 40, 42.

To supply the lower component space 40, a transverse passage site 44 isused, preferably in the form of a hole which connects the componentspace 40 to carry fluid to the interior of the filter housing 20, inparticular to the installation space 22 for the filter element 24. Fluidwhich has been filtered in this way is thus fed into the component space40 by way of the transverse passage site 44 and then flows from left toright through the fluid routing channels 14, cooling being induced bythe cooling unit 10 in its lower half area. The fluid or medium whichhas been cooled in this way then enters the other fluid collectingchamber 18, rises toward the top when viewed in the direction of lookingat FIG. 1, and then crosses the fluid routing channels 14 from right toleft in the upper area, in particular in the upper half of the coolingunit 10. The fluid medium which has then been completely cooled in thisway enters the second or upper component space 42 and from there thefluid which has been filtered and cooled leaves the fluid device via theoutlet 46 which has the same axial direction as the inlet 26 (comparethe partial representation as shown in FIG. 2).

The arrangement described in this way for the most part makes the fluidflow uniform both in the filter unit 12 and also in the cooling unit 10and in the two fluid collecting chambers 16, 18. In particular, slowlyflowing fluid can be filtered and cooled in this way without disruption,and due to the constantly maintained cross sectional characteristicsenergy-efficient filtering and cooling operation with the cooling deviceaccording to the invention are possible. As FIG. 2 shows in particular,the filter unit 12 with the fluid collecting chamber 16 can be producedin one piece, for example in the form of a diecasting, in order toconnect the unit which has then been produced in this way fluid-tight tothe remaining cooling unit 10 on its one face side by means of aconventional welding process. If the other boundary wall 38 is omitted,with the described cooling device according to the invention, even morequickly flowing media can be reliably managed, then preferably in thearea of the second fluid collecting chamber 18 an outlet (not shown)having to be provided for discharging the filtered and cooled fluid.With the cooling device according to the invention a unit of verycompact structure is formed which can be flexibly adapted to thedifferent filtering and cooling tasks without the fundamental structureof the cooling device having to be changed; this helps to save money.Otherwise the cooling device according to the invention is easy tomaintain and install; this in turn helps to save money.

1. A cooling device with a cooling unit (10) through which a fluid to becooled, especially hydraulic oil, can flow, and with a filter unit (12)for filtration of the fluid, the filter unit (12) extending on onelongitudinal side of the cooling unit (10) and a fluid collectingchamber (16) being located between the filter unit (12) and the coolingunit (10), characterized in that the fluid collecting chamber (16) has auniform flow cross section and is sealed relative to the filter unit(12) at least partially by a concavely curved boundary wall (36).
 2. Thecooling device according to claim 1, wherein the fluid collectingchamber (16) is made semicircular in cross section and wherein thefilter unit (12) has a filter element (24) which is held in a filterhousing (20) with a cylindrical installation space (22).
 3. The coolingdevice according to claim 2, wherein the fluid collecting chamber (16)in the middle has another boundary wall (38) which divides the fluidcollecting chamber (16) into two component spaces (40, 42), of which one(40) has a fluid connection (44) to the filter housing (20) and theother (42) has an outlet (26) for the discharge of filtered and cooledfluid.
 4. The cooling device according to claim 3, wherein the overalllength of the filter element (24) in the filter housing (20) correspondsroughly to the distance of the other boundary wall (38) of the twocomponent spaces (40, 42) from their ends.
 5. The cooling deviceaccording to claim 1, wherein there is another fluid collecting chamber(18) on the longitudinal side of the cooling unit (10) opposite thefilter unit (12).
 6. The cooling device according to claim 1, whereinthe filter housing (20) together with the fluid collecting chamber (16)forms a one-piece unit which can be connected to the cooling unit (10)as another unit.
 7. The cooling device according to claim 2, wherein thefilter element (24) is supported within the filter housing (20) on aspacer layer (30) which is held by a holding unit (32) which is in turnsupported on the bottom part (34) of the filter housing (20).